package org.dfg.corejava.jdk7.aio.chatserver;

/*
 * Copyright (c) 2011 Oracle and/or its affiliates. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * - Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 * 
 * - Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * - Neither the name of Oracle nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior
 * written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This source code is provided to illustrate the usage of a given feature or
 * technique and has been deliberately simplified. Additional steps required for
 * a production-quality application, such as security checks, input validation
 * and proper error handling, might not be present in this sample code.
 */

import java.nio.ByteBuffer;

/**
 * The first state a newly connected {@code Client} is in, this handles writing
 * out the welcoming message and reads the response up to a newline. When a
 * newline character have been received it changes the handler from NameReader
 * to MessageReader on the client.
 */
class NameReader implements DataReader {
	private final StringBuilder buffer = new StringBuilder();
	private final ChatServer chatServer;
	private boolean once = true;
	private static final String NEWLINE = "\r\n";

	public NameReader(ChatServer chatServer) {
		this.chatServer = chatServer;
	}

	/**
	 * Writes the welcoming message to the client the first time this method is
	 * called.
	 *
	 * @param client the client to receive the message
	 */
	@Override
	public void beforeRead(Client client) {
		// if it is a long name that takes more than one read we only want to
		// display Name: once.
		// 第一次连接，发送提示
		if (once) {
			client.writeStringMessage("Name: ");
			once = false;
		}
	}

	public boolean acceptsMessages() {
		return false;
	}

	/**
	 * 读取用户输入的昵称 Receives incoming data from the socket, searches for a newline
	 * and tries to set the username if one is found
	 */
	@Override
	public void onData(Client client, ByteBuffer buffer, int bytes) {
		buffer.flip();
		String name;
		// 一次可能读不完，所以用StringBuilder缓存
		name = this.buffer.append(new String(buffer.array(), 0, bytes)).toString();
		if (name.contains(NEWLINE)) {
			onUserNameRead(client, name);
		}
	}

	/**
	 * Splits the name on the newlines, takes the first as the username and
	 * appends everything else to the clients message buffer. Sets the clients
	 * handler to MessageReader.
	 *
	 * @param client the client to set the username for
	 * @param name the string containing the buffered input
	 */
	private void onUserNameRead(Client client, String name) {
		String[] strings = name.split(NEWLINE, 2);// 匹配2-1次
		client.setUserName(strings[0].trim());
		sendRemainingParts(client, strings);
		client.setReader(new ClientReader(chatServer, new MessageReader(chatServer)));// 替换DataReader，进入聊天模式
		client.writeStringMessage("Welcome " + client.getUserName() + "\n");
	}

	/**
	 * Appends the remaining parts to the clients message buffer
	 *
	 * @param client the client
	 * @param strings the messages to append to the buffer
	 */
	private void sendRemainingParts(Client client, String[] strings) {
		for (int i = 1; i < strings.length; ++i) {
			client.appendMessage(strings[i]);
		}
	}
}
